Guided Inquiry Lesson Plan #3: The Jar and Water Test

Length of Lesson: One class period

Scientific Processes Addressed: Predicting, Observing, Measuring, Calculating, and Communicating

Science Concepts Addressed: Soil Composition

National Standards Addressed: A, B, D

Objectives: Students will be able to:

1. Observe the layering effect that the soil is forming as is settles.

2. Measure the depths of each layer of soil.

3. Calculate the percentage that each layer accounts for in the total soil sample.

Materials:

1 quart jar with straight sides and a lid.

2 cups of soil

1 tsp (5 mls) of water softener (Calgon)

Tap water

Ruler

Introductory Activity: Have the students get in their groups and discuss how they think the soil will settle. Then have each group share their ideas with the class. Write each different idea on the board for all to see.

Description of Activities: The Jar and Water test is one good way to determine the texture of soil.

  1. Take your soil sample, break up the clods and remove the deris.
  2. Put 2 cups of the soil in a jar and add 1 tsp (5 mls) of water softener. This will help break up the particles.
  3. Fill up the jar with tap water, put the lid on tightly and shake the jar until all the soil particles are suspended in the water.
  4. After one minute, measure the depth of the sediment on the bottom. This is the sand layer.
  5. In two hours, measure the layer of sediment that will be lying on top of the sand. This is the silt layer.
  6. After 24 hours, measure the third layer on the top. This will be the clay layer. Most of the organic matter will float on the surface of the water.
  7. Now you are to figure out the percentages of sand, silt and clay in your soil sample. Divide the depth of each layer you measured by the total depth of the soil in the jar. Multiply each number by 100 to get a percentage.

For example, The layer of sand is ¾ inch and the total sample is 3 inches. The sand accounts for .25, or 25% of the total soil sample.

Expected Conclusions: Students will be able to explain the following:

Soil comes in many different types. Types of soil are differentiated by the content and amount (percentages) of each element in the varying types of soil. (ie: soil can be made up of sand, silt, clay and other elements.)

Assessment: Will be based on student interaction in cooperative groups, and on their ability to observe, measure and calculate the percentages of each soil layer.

Extensions:

Language Arts – In their journals, have the students describe what they observed after the soil settled after 2 hours and after 24 hours.

Social Studies - The Mississippi River sends tons of silt and soil washed from farmers’ fields into the Gulf of Mexico each year. Use your resources to confirm this statement, and find out any other information you can about this.

Computer Skills - You may use the Internet to help you with the above search.